Diaminomethylenemalononitrile organocatalysts promote the asymmetric chlorination of simple cyclic beta-keto esters such as methyl, ethyl, and benzyl esters of 1-oxo-2,3-dihydro-1H-indene-2-carboxylic acid. This affords the corresponding chiral alpha-chlorinated carbonyl products in excellent yields with high enantioselectivities.
Chiral imidodiphosphoric acids were employed as catalysts for the enantioselective α-chlorination of β-keto esters and amides using NCS as the chlorine source, providing a series of optically active products with good to high enantioselectivities (74–95% ee) and excellent yields (92–99%). This represents the first report of the Brønsted acidcatalyzed enantioselective α-chlorination of cyclic β-keto
Stereoselective α-Chlorination of β-Keto Esters in the Presence of Hybrid Amide-Based <i>Cinchona</i> Alkaloids as Catalysts
作者:Maciej Majdecki、Piotr Grodek、Janusz Jurczak
DOI:10.1021/acs.joc.0c02486
日期:2021.1.1
by hybrid amide-based Cinchona derivatives. The chlorination process proceeds with proper quantitative yields (up to <99%) and high asymmetric induction (up to 97% ee). We show that the use of only 0.5 mol % hybrid catalyst based on a Cinchona core allows the chlorination reaction to be conducted in a highly enantioselective manner with various indanone and tetralone carboxylate esters.
Simple Cinchona alkaloids serve as nucleophilic organocatalysts to facilitate the enantioselective α‐chlorination of β‐keto esters by using hypervalentiodine‐based Cl‐transfer reagents